1. Field of the Invention
This invention relates in general to the field of Universal Serial Bus (USB) devices, and more particularly to USB module capable of enabling or disabling a link path between a USB host and a USB device.
2. Description of the Related Art
There are literally hundreds of present data devices that communicate with a host computer via the Universal Serial Bus (USB) protocol. And not only does the USB protocol provide for communications between devices, but it also prescribes a number of charging modes, so that a portable device can be recharged as well as communicate over a USB bus.
Consider for example the ubiquitous iPhone®. When coupled to a host computer via a USB bus, the operations of syncing with an iTunes® library can be accomplished, while at the same time recharging the battery within the iPhone.
But, as one skilled in the art will appreciate, there are a number of factors that impede optimal charging of USB devices, such as the inability of a USB host or USB hub to charge a corresponding USB device when the USB host is in a power saving state. In addition, a present day USB hub is incapable of charging a downstream USB device when the USB hub is disconnected from a USB host. Finally, because prevailing USB charging specifications only prescribe a limited number of charging modes, most USB devices cannot be charged in an optimal manner.
Accordingly, what is needed is a mechanism that allows optimal charging of specific USB devices.
Also what is needed is a mechanism for optimally charging a USB device that is connected with a USB hub, where charging can be affected in the absence of a USB host.
Furthermore, what is needed is a USB charging module that is disposed in a USB hub, where charging can be affected when a connected USB host is in a power saving state.
Moreover, what is needed is a USB charging technique within a USB host, where charging can be affected when the USB host is in a power saving state.